This invention relates to the field of total internal reflection devices and more particularly to a integrated fiber array optical switch using double-pass propagation.
Fiber-optic communication systems include optical components, such as optical fibers coupled to switching components, that receive, transmit, and otherwise process information in optical signals. The switching components in a fiber-optic communication system selectively direct the information carried by the optical signal to one or more other optical components. A problem with existing fiber-optic communication systems is that they require many complex optical components to perform the switching function. This adds to the cost and size of the fiber-optic communication system. It also leads to slower switching speeds and difficulties with aligning the switching components.
An integrated fiber array optical switch is provided that substantially eliminates or reduces disadvantages and problems associated with previous optical switches.
In accordance with one embodiment of the present invention, an optical switch includes an input member, a reflective output member coupled to the input member, and a transmissive output member. The input member supports a plurality of input waveguides, each input waveguide having a reflective surface and operable to receive a corresponding optical signal. The reflective output member supports a plurality of first output waveguides, each first output waveguide coupled to a corresponding input waveguide. The transmissive output member supports a plurality of second output waveguides and has a first position spaced apart from the input member such that the reflective surface of each input waveguide totally internally reflects a corresponding optical signal to a corresponding one of the first output waveguides, and a second position in proximal contact with the input member such that each second output waveguide frustrates the total internal reflection of a corresponding optical signal and receives a corresponding optical signal.
Another embodiment of the present invention is an optical switch that includes an input member, a reflective output member coupled to the input member, and a transmissive output member. The input member supports a first input waveguide, a second input waveguide, a first output waveguide, and a second output waveguide. The first input waveguide has a reflective surface and receives a first optical signal and the second input waveguide has a reflective surface and receives a second optical signal. The reflective output member supports a first return loop waveguide that couples the first input waveguide to the first output waveguide, and a second return loop waveguide that couples the second input waveguide to the second output waveguide. The transmissive output member supports a third return loop waveguide that couples the first input waveguide to the second output waveguide, and a fourth return loop waveguide that couples the second input waveguide to the first output waveguide.
The transmissive output member has a first position spaced apart from the input member such that the reflective surface of the first input waveguide totally internally reflects the first optical signal to the first return loop waveguide for communication to the first output waveguide and the reflective surface of the second input waveguide totally internally reflects the second optical signal to the second return loop waveguide for communication to the second output waveguide. The transmissive output member also has a second position in proximal contact with the input member such that the third return loop waveguide frustrates the total internal reflection of the first input waveguide and receives the first optical signal for communication to the second output waveguide and the fourth return loop waveguide frustrates the total internal reflection of the second input waveguide and receives the second optical signal for communication to the first input waveguide.
Yet another embodiment of the present invention is an optical switch that includes a first input member, a first reflective output member coupled to the first input member, a first transmissive output, a second input member, a second reflective output member coupled to the second input member, and a second transmissive output.
The first input member supports a first input waveguide having a reflective surface and operable to receive an optical signal. The first reflective output supports a first intermediate waveguide coupled to the first input waveguide. The first transmissive output member supports a second intermediate waveguide and has a first position spaced apart from the input member such that the reflective surface of the input waveguide totally internally reflects the optical signal to the first intermediate waveguide, and a second position in proximal contact with the input member such that the second intermediate waveguide frustrates the total internal reflection of the input waveguide and receives the optical signal.
The second input member supports the first intermediate waveguide having a reflective surface and the second intermediate waveguide having a reflective surface. The second reflective output member supports a first output waveguide coupled to the first intermediate waveguide and a second output waveguide coupled to the second intermediate waveguide. The second transmissive output member supports a third output waveguide and a fourth output waveguide, and has a first position spaced apart from the second input member and a second position in proximal contact with the second input member.
Another embodiment of the present invention is an optical switch that includes an input member, a reflective output member coupled to the input member, and a transmissive output member. The input member supports an input waveguide having a reflective surface and operable to receive an optical signal. The reflective output member supports a first output waveguide and a return loop waveguide that is coupled to the input waveguide and the first output waveguide. The transmissive output member supports a second output waveguide and has a first position spaced apart from the input member such that the reflective surface of the input waveguide totally internally reflects the optical signal toward the return loop waveguide for communication to the first output waveguide. The transmissive output member further has a second position in proximal contact with the input waveguide such that the second output waveguide frustrates the total internal reflection of the optical signal and receives the optical signal.
Technical advantages of the present invention include an optical switch that switches one or more optical signals using waveguides. By using waveguides to guide an optical signal to the switching region and to perform the switching operation, the present invention eliminates the need for costly and sometimes complex optical components. This results in a smaller packing density for the optical switch of the present invention and a more efficient, faster switching operation.
Another technical advantage provided by the present invention is that the optical switches described herein support an array of input and output waveguides to facilitate the simultaneous switching of multiple channels of an optical switch using a common actuator. Yet another technical advantage provided by the present invention is that by cascading a number of optical switches in a particular arrangement, and by selectively operating each individual optical switch, an Nxc3x97M optical switch may be constructed.
While in a switched state, the contact surface of a waveguide is typically placed in proximal contact with a reflective surface of another waveguide to frustrate the total internal reflection of the optical signal. A small portion of the optical signal may be reflected, however, at the reflective surface and processed as though the switch is operating in the unswitched state. This undesired result is one source of a cross-talk signal in the system.
Another technical advantage provided by the present invention is that the optical switches described herein reduce the effects of a cross-talk signal generated by the above-identified reflection. In particular, the optical switches of the present invention process any cross-talk signals so that a large portion of a cross-talk signal is not received by an optical component of the optical switch. The negative effects of a cross-talk signal are thereby reduced.
For example, in the switched state, an undesired cross-talk signal resulting from a residual reflection at the FTIR interface between a reflective surface and a contact surface is further processed by a return-loop waveguide to reduce the crosstalk signal intensity. In particular, the crosstalk signal radiation is conveyed by the return-loop waveguide to a second FTIR interface within the output waveguide signal path. In the switched state this second FTIR waveguide interface frustrates the total internal reflection of the crosstalk signal at the reflective surface of the output waveguide. As a result, the small, undesired residual portion of the original optical signal undergoes further reduction in its intensity at this second FTIR interface. Therefore, only a negligible portion of the original optical signal, if any, comprises a crosstalk signal that may actually reach an optical component of the switch. Thus, the crosstalk signal is dissipated and its effects become negligible. This technique is referred to as double-pass propagation. The reduction in the magnitude of the crosstalk signal in the present invention will be referred to as a crosstalk improvement.
Other technical advantages are readily apparent to one skilled in the art from the following figures, descriptions, and claims.